At the Transient Journal Club meeting on April 22 1997, we began looking at various classes of transient sources to try to develop a strategy for learning about them, and about how we at LANL might contribute to the science of such sources. This note represents a summary or codification of what we put on the board during that meeting, and our intentions in designing and filling out the matrix of characteristics of transient sources. Comments on this are invited, of course!
We agree that the science of transient astrophysics consists of three parts:
Phenomenology stands in the middle because it is easiest to get at, drives the observing techniques, and is our handle on the physics. For most (but not necessarily all) classes of transients, phenomenology includes such things as timescales, spectral information, total energies, fluxes, etc.
Physics, however, is fundamental to our interest in these sources, and the nature of our physics interest depends on the class of source. In some cases (1), we want to understand the physics of the transient phenomenon itself, and we look in great detail at specific exemplars of that phenomenon. In other cases (2), we use that phenomenon (which we may or may not understand well) to characterize the physics of the parent population of objects which exhibit the same phenomenon, and we collect large samples of objects to compare. In yet other cases (3), we use the population of particular transient sources as tracers for a larger-scale physical phenomenon (such as galactic structure or cosmology). Note that this subdivision quite deliberately blurs the old distinction between astronomy (describing, classifying, cataloging, and locating populations of celestial objects) and astrophysics (using the laws of physics to understand the nature of celestial objects).
We wrote down a large number of types of transient sources, dividing them as to how well we think we understand the physics of the sources (quite a subjective division!). In parentheses I've put the initials of someone who volunteered (or was volunteered) to fill out the template by answering the questions below.
Poorly known physics
Somewhat better known physics
Fairly well understood physics
For each of these classes of sources we should attempt to answer the following:
As an example, we attempted to answer just question (1) for flare stars. Here's what we came up with, subdivided into our general classification of physics, phenomenology, and implementation. Many of the questions will be similar for many of the classes of sources.
What are the interesting questions for flare stars?
If there's anything I've forgotten, please forgive me, but let me know.